JPH0353810Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a resistance welding gun used for car body welding and the like.

(Prior technology) Conventionally, this type of welding gun was
According to Publication No. 29808, a machine is provided with a movable gun arm connected to a piston rod of an operating cylinder, a fixed gun arm facing the movable gun arm in the axial direction of the piston rod, and a cam plate having a cam groove for guiding the movable gun arm. A longitudinal guide bar is installed in the axial direction of the piston rod on a bracket erected on the base, and the cylinder barrel of the operating cylinder is slidably supported by the guide bar in a guide sleeve formed on the outer surface of the cylinder barrel, Attach the cam plate to the cylinder barrel, and attach the fixed gun arm to the cam plate, and by operating the operating cylinder, guide the movable gun arm into the cam groove and close it toward the fixed gun arm. The movable gun arm comes into contact with the workpiece, and then, due to the contact reaction force, the cylinder barrel, and therefore the fixed gun arm attached to it via the cam plate, are drawn toward the movable gun arm, and the workpiece is placed between the two gun arms. It is known to be clamped and then welded.

In this device, a stopper is fixed at the tip of the bracket that engages with a step formed on the piston rod during the opening operation of the movable gun arm, and the reaction force of the step against the stopper causes the cylinder barrel to move. The end of the guide sleeve is pushed in a direction away from the movable gun arm so that even if the fixed gun arm is welded to the workpiece, it can be peeled off from the workpiece, and the guide bar is formed in the cylinder barrel so that the fixed gun arm opens. A stopper is attached to abut on and restrict the movable gun arm from the workpiece even if the movable gun arm is welded to the workpiece by the reaction force of the guide sleeve against the stopper.

(Problem to be solved by the invention) In the above device, the first stopper for separating the fixed gun arm from the workpiece and the second stopper for separating the movable gun arm from the workpiece are connected to a bracket and a guide bar, respectively. The cam groove needs to be attached to the movable gun arm, which increases the number of parts, and in order to prevent the movement of the fixed gun arm from pulling the fixed gun arm toward the movable gun arm due to the reaction force from contact with the workpiece when the movable gun arm closes. It is necessary to extend the cam plate in the axial direction of the piston rod by the operating stroke of the cam plate, which increases the size of the cam plate and the overall weight of the gun.

The purpose of the present invention is to solve these problems and provide a welding gun with a simple structure, small size, and light weight.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a movable gun arm connected to a piston rod of an actuating cylinder, a fixed gun arm facing the movable gun arm in the axial direction of the piston rod, and a movable gun arm connected to the piston rod of the working cylinder. A cam plate having a cam groove for guiding a movable gun arm is provided, and a guide bar elongated in the axial direction of the piston rod is attached to a bracket set upright on the machine base, and the cylinder barrel of the operating cylinder is attached to the guide bar. In one that is slidably supported by a guide sleeve formed on the outer surface of the barrel,
The cam plate is fixed to the bracket, and the fixed gun arm is fixed to the cylinder barrel, and the opening operation of the fixed gun arm is caused to contact the end of the guide sleeve at the mounting base of the bracket to the machine base. It is characterized by integrally provided with a stopper for regulating the temperature.

(Function) When the movable gun arm is closed by the operation of the operating cylinder, after the movable gun arm contacts the workpiece, the reaction force of the contact causes the cylinder barrel of the operating cylinder, and therefore the fixed gun arm fixed thereto, to move. It is pulled toward the gun arm side and comes into contact with the workpiece, and the workpiece is clamped between the two gun arms.
In this case, since the cam plate is fixed to the machine base rather than the cylinder barrel, the cam plate does not move relative to the movable gun arm when the fixed gun arm is pulled in, and the length of the cam groove formed in the cam plate does not occur. It is sufficient that the length corresponds to the operating stroke of the movable gun arm.

Also, when the opening operation of the movable gun arm reaches the end of the operating stroke, which is regulated by the cam groove,
The cam plate functions as a stopper to push the cylinder barrel away from the movable gun arm, and even if the fixed gun arm is welded to the workpiece, it can be reliably separated from the workpiece. When the movable gun arm is welded to the workpiece, first the cylinder barrel moves to open the fixed gun arm, and when the end of the guide sleeve comes into contact with the stopper provided integrally at the mounting base of the bracket, the stopper is applied with a reaction force. The movable gun arm acts as a receiver and is pushed toward the open side to separate it from the workpiece.

(Embodiment) Referring to FIG. 1, 1 is a machine base consisting of a welding jig, etc., 2 is an operating cylinder, and 3 is a movable gun arm 4 connected to a piston rod 2a of the operating cylinder 2, which is connected to the movable gun arm 3. A fixed gun arm 4 is shown facing the piston rod 2a in the axial direction, and in the illustrated example, the movable gun arm 3 and the fixed gun arm 4 are vertically opposed to each other with the axial direction being the vertical direction. electrode 3
The working cylinder 2 is configured to clamp and weld the workpiece W from above and below by means a and 4a, and the piston 2b at the lower end of the piston rod 2a is fitted inside the working cylinder 2.
The cylinder barrel 2c of FIG. 1, FIG. 2 and FIG.
As shown in the figure, a guide bar 9 attached to a bracket 8 erected on the machine base 1 is supported by a guide sleeve 2f formed on the outer surface of the cylinder barrel 2c so as to be slidable in the vertical direction. The bracket 8 includes a pair of supporting legs 8b, 8b rising from a mounting base 8a at the lower end relative to the machine base 1, and a guide bar 9 is erected between the supporting legs 8b, 8b.
A stopper 8c for inserting the lower end of the guide bar 9 is integrally provided in the mounting base 8a, and by bringing the lower end of the guide sleeve 2f into contact with the stopper 8c, the downward opening movement of the fixed gun arm 4 is restricted. did.

The movable gun arm 3 is equipped with an arm holder 3b bolted to the lower surface of its root, and a pair of upper and lower guide pins 3c, 3c are horizontally installed in the holder 3b, and both guide pins 3c, 3c are connected to the holder 3b. As shown in FIGS. 1 and 3, cam grooves 5a, which are longitudinal in the vertical direction, are formed in a pair of left and right cam plates 5, 5.
5a, and the upper end of the piston rod 2a is pivotally connected to the lower guide pin 3c as shown in FIGS.
By the vertical movement of a, the movable gun arm 3 is given an upward opening action and a downward closing action guided by the cam groove 5a.

Here, both cam plates 5, 5 are bolted to both sides of a support frame 8d fixed between the upper ends of the support legs 8b, 8b, as shown in FIGS. 1 and 4, and As shown in FIG. 1, the fixed gun arm 4 is bolted to the upper surface of the overhang at the upper end of the cylinder barrel 2c.

In the drawing, 2d and 2e are first and second air ports 6 for supplying and exhausting air to the upper and lower chambers of the operating cylinder 2, respectively.
indicates a power supply cable to each gun arm 3, 4, and 7 indicates an insulating material.

Next, to explain the operation of the above embodiment, when welding, first the welding gun is opened as shown in FIG. Air is forced into the air port 2d to move the piston rod 2a downward, giving the movable gun arm 3 a downward closing motion.According to this, the lower guide pin 3c is a little closer to reaching the lower end of the cam groove 5a. The electrode 3a of the face movable gun arm 3 comes into contact with the upper surface of the workpiece W, and then receives a reaction force from the contact and moves into the operating cylinder 2.
The cylinder barrel 2c moves upward relative to the piston rod 2a, the fixed gun arm 4 is drawn toward the movable gun arm 3, and the electrode 4a of the fixed gun arm 4 comes into contact with the lower surface of the workpiece W, as shown in the first figure. The workpiece W is connected to the electrodes 3a of both gun arms 3 and 4,
4a from above and below, both electrodes 3a, 4a
The workpiece W is welded by energization during this period.

After welding is completed, air is forced into the lower chamber of the working cylinder 2 from the second air port 2e. In this case, normally the cylinder barrel 2c is connected to the piston rod 2a.
The fixed gun arm 4 opens downward by moving downward against the
When the lower end of the guide sleeve 2f comes into contact with the stopper 8c, the piston rod 2a moves upward, and even if the electrode 3a of the movable gun arm 3 is welded to the workpiece W, the pushing up force of the piston rod 2a will cause the electrode 3a to move away from the workpiece W. By peeling off, the movable gun arm 3 is opened upward. Electrode 4 of fixed gun arm 4
If a is welded to the workpiece W, first the movable gun arm 3 is opened by the upward movement of the piston rod 2a, and the upper guide pin 3c reaches the upper end of the cam groove 6a, and the movable gun arm 3 is moved no further. When the piston rod 2a is no longer opened, the cam plate 5 functions as a stopper, and a downward pressing force is applied to the cylinder barrel 2c against the piston rod 2a, and this pressing force causes the electrode 4 of the fixed gun arm 4 to
a is peeled off from the workpiece W, and the fixed gun arm 4
is opened downward.

Here, the operating stroke of the movable gun arm 3 is defined by the length of the cam groove 5a, and the fixed gun arm 4 is operated within a stroke obtained by subtracting the operating stroke of the movable gun arm 3 from the stroke of the piston 2b of the operating cylinder 2. It turns out.

(Effects of the invention) As described above, according to the invention, since the cam plate is fixed to the machine base via the bracket, there is no need for a separate stopper to restrict the opening movement of the movable gun arm, and the length of the cam groove is The cam plate can be made smaller by shortening the length, and the stopper that restricts the opening movement of the fixed gun arm is integrated into the mounting base of the bracket to the machine base, so the structure is much simpler than the conventional example in which the stopper is attached to the guide bar. This can be simplified, and when the movable gun arm is welded to the workpiece, the pressing force of the operating cylinder acting on the stopper can be stably received at the mounting base, and there is an effect that no strain is applied to the guide bar or the bracket.

[Brief explanation of the drawing]

Figure 1 is a cutaway side view of an example of the welding gun of the present invention.
Fig. 2 is a rear view of the welding gun seen from the left side of Fig. 1, Figs. 3 to 5 are cross-sectional views cut along the line - to - of Fig. 1, respectively, and Fig. 6 is the welding gun in an open state. FIG. 1... Machine base, 2... Operating cylinder, 2a... Piston rod, 2c... Cylinder barrel, 2f...
...Guide sleeve, 3...Movable gun arm, 4...
...Fixed gun arm, 5...Cam plate, 5a...
...Cam groove, 8...Bracket, 8a...Mounting base, 8c...Stopper, 9...Guide bar.

Claims (1)

[Scope of utility model registration request] a movable gun arm connected to a piston rod of an operating cylinder; a fixed gun arm facing the movable gun arm in the axial direction of the piston rod;
A cam plate having a cam groove for guiding the movable gun arm is provided, a guide bar extending in the axial direction of the piston rod is attached to a bracket set upright on the machine base, and the cylinder barrel of the operating cylinder is attached to the guide bar. In a cylinder barrel that is slidably supported by a guide sleeve formed on the outer surface of the cylinder barrel, the cam plate is fixed to the bracket, the fixed gun arm is fixed to the cylinder barrel, and the bracket is attached to the machine base. A resistance welding gun, characterized in that a stopper is integrally provided on the mounting base to restrict the opening movement of the fixed gun arm by coming into contact with the end of the guide sleeve.